1. Field of the Invention
The present invention relates to a socket and method of making the same, and particularly to a SO DIMM socket with contact having a hook extending curvedly to hold solder ball.
2. Description of Related Art
A typical SO DIMM (Small Outline Dual In-line Memory Module) socket be soldered to a printed circuit board is described in U.S. Pat. No. 6,575,763, issued to Choy on Jun. 10, 2003. The connector comprises a housing, a plurality of contacts received therein and a plurality of solder balls attached to the contacts respectively. The solder ball is soldered to the tail of a contact and be soldered to the printed circuit board.
When conducting a soldering process, there is dilemma. At one hand, it is requested that the tail of the contact expresses solderable property, i.e. the solder ball can be readily and easily attached thereto. If the solder joint is not properly formed between the tail and the solder ball, defective interconnection or so called cold-joint will encounter. Reworking process will always be needed to correct this problem. On the other hand, because of this solderable property, the solder ball tends to flow upward or wick along an external surface of the tail. Once the solder flows and wicks upwardly along the surface resulted from the capillary force, the overall characteristic of the contact terminal will be changed or negatively modified. For example, when the contact is designed, intended normal force, deflection, etc have been carefully calculated so as to meet the field requirements. Once the solder flows and wicks upward to cover the contact, the characteristic of the contact will be altered, and the normal force and other properties will be altered accordingly.
Hence, it is desirable to provide an improved socket to overcome the aforementioned disadvantages.